This report involves an investigation of the synthesis of a copolymer composed of 2-ethylhexyl acrylate (2-EHA) and acrylic acid (AA) by pulsed electron beam and gamma irradiation. Pulsed electron beam is employed as a method of curing acrylate ester polymers for a wide variety of fields in adhesive, coating, ink and lithographic applications. The rate of reaction may be controlled through manipulation of the dose rate, pulse width and frequency, and this approach has been demonstrated to provide more rapid and uniform curing than thermal curing techniques. Although there have been several reports of the initiation and propagation steps of the free radical copolymerization of 2-EHA and AA, there is still considerable misunderstanding of these phenomena and further investigation is required to establish the fundamental process taking place during the synthesis of this polymer. Pulse radiolysis has been employed to study the fast kinetics and structure of radiation-induced ions and free radicals during the synthesis of poly(2-ethylhexyl acrylate-co-acrylic acid). This technique involves irradiation of the monomers with a single pulse of electrons to provide the initial concentration of excited and ionized species, followed by the monitoring of their decay by time-resolved spectrophotometry. This method is particularly useful in analysis of the initiation and early stages of the polymerization reaction. The structure and composition of the copolymer produced under pulsed and steady state irradiation conditions has been studied by 1H NMR and FTIR as a function of dose, dose rate, and concentration of acrylic acid. Low dose rate experiments were performed using gamma radiation from a 60Co source, and high dose rate experiments were performed using a linear electron accelerator. In addition, the reactions initiated by electron beam irradiation were studied as a function of pulse width and pulse repetition rate.

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